Fanboy and Chum Chum have a test coming up and if the entire class passes, they win a bouncy house. Fanboy decides to install his brain into Oz's robot to get smarter, but worse results come to follow.

When a heatwave hits Galaxy Hills, the boys see the Frosty Freezy Freeze machine is on the fritz. They try to nurse Berry, the ice monster who runs the machine back to health but wind up getting "Frosty Freezy Freeze Fever" the moment they lick him.

Fanboy and Chum Chum take home and care for the class pet pig, Precious. But Mr. Mufflin catches Fanboy teaching him kung fu and thinks he's hurting him, so he takes Precious back and Fanboy can no longer care for him.

Kyle is not pleased when his old rival, Sigmund the Sorcerer, shows up in Galaxy Hills. And when Sigmund comes over to his place for dinner, Kyle tries to pass Fanboy and Chum Chum off as his elf assistants.

On March 12, 2010, the series was picked up for a second season of 26 episodes.[1]The writers of the series said they started writing season two on February 1, 2010. On April 1, 2011 Frederator Studios announced that the first four episodes of Season 2 will premiere from April 25, 2011 to April 28, 2011, starting with "I'm Man-Arctica!" and "No Toy Story" and ending with "GameBoy" and "The Big Bopper".

This season consists of 22 episodes split up into segments, plus the first four half-hour episodes: Brain Freeze, There Will Be Shrieks, A Very Brrr-y Icemas and Super Chums.

Since February 11, 2012, the show has been airing episodes worldwide before the US.

With Class Picture Day in full swing, Fanboy and Chum Chum want the photo to be hilarious, and Fanboy made the funniest face yet. Fanboy has to keep the face for the entire day so he doesn't lose it, but it keeps getting him in trouble and Hank will do nothing but try to ruin the photo.

It's Agent Johnson's birthday, and Lenny baked some dynamo chip cookies to try and get a raise. When he goes on errands and leaves Dollarnator in charge of guarding the treats, Fanboy and Chum Chum will stop at nothing to steal them.

Fanboy and Chum Chum wake up one morning to discover they are speaking and doing things at exactly the same time. Oz says they're in Paladise, a state where two friends grow like they are only one. The boys enjoy it, but when they suddenly "fall out" of Paladise, they try to get it back before it's gone for good.

The entire town is participating in the Frosty Mart Sweepstakes, where there are prizes -- one of them has a million Frosty Bucks. When Fanboy and Chum Chum sip the winning cup, they try to redeem the prize before an angry anxious mob of residents steal it from them.

Kyle is upset when Sigmund releases a new video game, "Sigmund the Sorcerer's Wizard Challenge", until he finds out whoever wins the game gets an admission to Milkweed as the prize. With the help of Fanboy and Chum Chum and their ultimate video game skills, Kyle tries to beat the game without beating himself up.

After Fanboy takes over Kyle's position as Hank's Board Eraser-er, Kyle gets back at him by giving him a special eraser that literally erases anything. However, instead of Fanboy getting in trouble, he has an awesome time erasing everything in sight. Kyle will stop at nothing to get Fanboy to learn his lesson on eraser-ering.

Fanboy and Chum Chum suddenly go into a debate over whether superheroes or supervillains would be good for them. As a result, Fanboy transforms into a villain named Fannihilator and Chum Chum becomes a hero called Super Chum. Now, the boys have to face off against each other to determine which side is better.

Yo is throwing a slumber party at her house, but Fanboy and Chum Chum are not invited because it's a girls only sleepover. Fanboy begins to believe that the girls are actually aliens who are planning to eat their faces, so he and Chum Chum go to the party disguised as girls to get proof.

Fanboy and Chum Chum go camping with Man-Arctica as his Man-Arctic Seal Cubs, but they are too cold in the freezing cold arctic tundra where the camp takes place. When they see Global Warmer's warm camp across the lake, they try to sneak over there without Man-Arctica noticing.

Kyle does not get chosen for the "Buddy System" for a field trip to the Dinosaur Museum, so Fanboy and Chum Chum have him be a part of theirs. And when they accidently fall off the bus and get lost in the desert, they have to put their buddy skills to the test if they want to escape.

After Fanboy and Chum Chum discover they've been wacky all this time and haven't learned to act normal, they decide to change their image and act normal and proper for one entire day. Their new attitude suddenly becomes seemingly obsessive as they try have privacy because they are now unable to help their friends and get used to everything silly.

Fanboy and Chum Chum recieve the new toy, Mega Mic, and learn that it makes their own sound effects rather than auto-tune their voices. The boys enjoy having fun with it, but they must stop when the microphone starts making sound effects on its own and turns against them.

Boog has to dress up as a giant Frosty Freezy Freeze for his job one day, and when Fanboy and Chum Chum meet him, they mistake him for the Frosty Mart's mascot, Freezy. Boog will do anything to dodge their constant frenzies and leave them alone.

In this superhero cartoon parody of the series, Super Chum faces a new villan, Copy Kitten, who threatens to replace Fannihilator as arch nemisis. The two team up together to rescue Professor Oz and stop Copy Kitten from stealing Super Chum's powers and become the new nemisis forever.

After Fanboy is banned from the field trip to the thermometer factory due to getting detention for his science project failing, Chum Chum uses his cloaning ray to clone themselves so they don't have to stay behind. But things get bad when the clones repeatedly clone themselves and wreck havoc on the entire town.

Fanboy and Chum Chum decide to start their own Super Awesome Club, but no one shows up, as they joined a Secret Club instead. The location is unknown, so the boys go on a wild fun-house like adventure while trying to find the location of the club.